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3 Sheets-Sheet 3.

` H.. s. MAXIM.

PROJBGTILE.-

Patented Dec. Z3, 1890.

(No Modvel.)

P m u I tu: wams Pszns no., Waremme., msnwcvon, u, c,

UNITED STAT-ns Pernaut Graneno lllRAM STEVENS )li'\X lM, OF LONDON, ENGLAND.

VPROM-:chte

SPECIFICATION forming part of Letters Patent No. 443,101, dated December 23, 1890.

Application filed April ll, 1890. Serial No, 347,495. (No model.)

T0 all whom t may concern.'

Be it known that I, HIRAM STEvENs Mnxin, mechanical engineer, a citizen of the United States, and a resident ot' London, England, have invented certain new and useful Improvements relating to Armor-Piercing and other Projectiles or Shells, of which the following is a specification, reference being had to the accompanying drawings.

My invention relates to armor-piercing and other projectiles or shells, and isV designed to aord the means for preventing or diminishing the rapid and destructive wear or erosion which takes place in guns wherein heavy charges of powder are employed with projectiles or shells as heretofore constructed. This destructive action or erosion usually occurs in the bore of the gun at or near the commencement of the riding thereof, and is due tothe escape or rush of the gases between the projectile and the barrel. It has been found that some of the most powerful guns heretofore constructed for armor-piercing are by such erosion rendered practically unserviceable after they have been used for firing, say, one hundred rounds, and that in some cases they are destroyed with much greater rapidity. By reason of this rapid wear and the enormous oost of manufacture of such guns the iiring of each individual shot involves a very large expenditure of money, the expenditure represented by the loss due to wear and tear of the gun being additional to and greatly exceeding that represented by the loss of the powder-charge and of the pro jectile when the latter is not recovered.

Tith a view to prevent the erosion of guns in the manner above mentioned, projectiles have heretofore been provided with a ring of copper or other suitable metal, designed, in some instances, to be expanded and intended to fit into the grooves of the riding and to serve as a gas-check, and also as adrivingring, whichV by its engagement with the riding will insure rotation of the projectile about its axis. Vhen, however, by the explosion of the powder-charge in the chamber of a gun a pressure of, say, twenty tons per square inch is set up in the said chamber, the tendency of the gas to escape between the projectile and the barrel is very great,

and the copper or other rings heretofore eniployed have not proved effective in the case of such high pressures-that is to say, although the said ring may serve its purpose as a driving-ring it does not act efficiently as a gas-check, chiefly for the following reason, viz: As very rapidrotation has to be imparted to the projectile in the short space of time which it takes to travel alongI the bore of the gun, the drivingring on entering the rifling is subjected to very great torsional and shearing stresses. Consequentlythe projections formed on the said ring are compressed and abraded by the driving side of the grooves of the rifling to such an extent that the said ring does not fit the said grooves with sufficient accuracy to completely close the space between the projectile and the interior surface or bore of the gun, small passages being left between the other side of the grooves andthe projections formed on the driving-ring. The rush of gas through the passages thus left rapidly erodes the steel of which the gun or the liner thereof is composed, and shortens to a very great extent the life of the gun, the steel being eaten away almost as rapidly as ice would be destroyed by a stream of boiling water.

Now the object of my invention is to provide for effectually preventing the escape or rush of gas between-the projectile or shell and the barrel, so that there will be but slight erosion of the steel tube or liner and the life of the gun will be greatly prolonged. To accomplish this result l provide for the complete obturation of the bore of the gun by means of a gas-check of soft or ductile metal or other yielding or plastic material, which is suitably arranged upon the projectile or shell in addition to the ordinary driving-ring of copper, or similar metal, which by its engagement with the riiing effects the rotation of the projectile. I arrange the said gas-cheek between the body of the projectile and a part which is movable relatively thereto in such a manner that when the said projectile is tired from a gun the gas-check will be subjected to pressure, and thus forced outward against the interior surface or bore of the gun. The employment of this gasfcheck in combination with an ordinary driving-ringis an important IOO feature of my said invention, as no metal which has sufficient strength to resist the torsional and shearing stresses to which the driving-ring is subjected by the rifling of the gun would be sufficiently ductile or plastic to be forced outward in such a manner as to fill up all the cavities or spaces between the projectile and the barrel.

I iind it advantageous to so construct my improved projectile that the front and rear portions thereof are movable longitudinally and capable of rotat-ion relatively to .each other and have between them one or more air chambers or spaces, and to arrange between the said two parts of the projectile a gas-check composed of one or more rings or annular pieces of soft or ductile metal or other suitable packing surrounding the said chamber or chambers, so that the surface of the rear portion of the projectile which bears against the said packing will be of less area than the surface thereof acted upon by the pressure in the chamber of the gun, and consequently in the firing of the projectile from a gun the pressure per square inch exerted upon the said packing will be correspondingly greater than that of the gases in rear of the proj ectile,as hereinafter more fully explained.

Vhen I make my projectile with two portions capable of rotation relatively to each other as above described, I sometimes provide the rear portion of the said projectile with a ring of copper or similar metal, which serves as a driving-ring to effect the rotation of the said rear portion of the projectile, and also acts efliciently as a gas-check.

In t-he accom pan yin g drawings I have shown how my said invention may be conveniently and advantageously carried into practice.

Figure l is a longitudinal central section, and Figs. 2 and 3 are side elevations, partly in longitudinal central section, showing different forms of projectiles orshells constructed according to my said invention.

ct is a portion of a rified gun.

A is the main portion or body of the said projectile or shell.

B is a cap or base secured to the rear end thereof, as hereinafter described.

C is a plug or block iixed in the rear end of the body A.

D is a screw-bolt for securing the cap or base B to the main portion or body A, while permitting it to move longitudinally and to rotate relatively thereto.

E is a driving-ring of copper or similar metal, such as those ordinarily used on projectiles or shells for large guns.

E is the ordinary steadying-ring.

F is a ring of copper or similar metal, which is secured to the movable cap or base B for the purposes hereinafter mentioned.

In the projectile shown in Fig. l the plug or block C is formed with an annular proj ection C', which tits into a corresponding recess or cavity B in the cap or base B in such a manner that the said cap or base can move a short distance forwardupon the said projection. 'lwo annular air-chambers G are thus formed between the two parts A B of the projectile. The said rear portion or base B is designed to be moved forward relatively to the body A when acted upon by the pressure of the gases generated by the explosion of the powder-charge in the gun, for the purpose hereinafter explained.

H H are two rings or annular pieces of lead or other soft or dnctile metal, or of sti fibrous packing or similar material, which are arranged between and bear against the adjacent surfaces of the said two parts A B of the projectile. Between these rings H H is arranged another ring or layer Ll', of softer or. more easily compressible or more plastic packing, consisting, for instance, of a mixture of asbestus, plumbago, Burgundy pitch, Russian tallow, and beeswax. This easily-compressible or plastic packing will at the commencementof the forward movement of the rear portion of the projectile relatively to the body thereof be forced outward against the interior surface or bore of the gun, and as the pressure to which the said rearportion of the projectile is subjected increases the rings of stiffer or harder packing will also be forced outward and will prevent escape of the softer packing between the projectile and the bore of the gun. These three rings of packing form the gas-check or obturator. It is obvious, however, that I can employ any other convenient number of rings of the same or other suitable material, if desired. The forward ring or annular piece I-I of soft metal or stiff fibrous packing may, if desired, be made slightly cup-shaped or formed with a thickened rim or ange extending a short distance forward, as shown.

The screw-bolt D for securing together the two parts A B of the projectile with the packing or gas-check between them is passed through the movable rear portion or base B IOO IIO

and screwed into the plug or block O in the forward portion or body A of the projectile, a gas-tight joint being made between the said bolt and the cap or base B by means of suitable packing, so that the said cap or base is free to slide upon the said bolt, while the entrance of gas to the airchamber G is avoided. For forming the said gas-tight joint I sometimes provide in the rear portion or base B an annular taper or conical chamber or recess B2, in which I place soft metal or other suitable packing K. In combination with this packingI providea disk or annular piece L, of soft metal or other suitable material, which is inserted in a dovetail recess or cavity in the rear portion or base B, or is otherwise secured thereto.4 When the said rear portion B is moved forward upon the bolt D, the pressure of the gases, acting upon the said disk L, will force the said disk and the packing into the said conical recess B2, and the packing will thus be tightly wedged against the said bolt, and will prevent the entrance of the gases into the chambers or spaces G. The said screw-bolt D can be used; if desired, for imparting an initial compression to the packing between the two parts of the projectile before the said projectile is inserted in the gun. The said bolt, moreover, affords the following advantage, viz: In target practice or in testing the gun or the gunmounting, when there is no necessity for great rapidity of firing, the projectile may be rammed into place in the gun -barrel with sufficient force to prevent its turning too freely in the barrel, and then the bolt D can be screwed up with a long spanner or in any other convenient manner, thus squeezing the packing or gas -check outward against the interior surface or bore of the gun. This operation very eifectually prevents any slight erosion that might take place by the gases escaping between the projectile and the barrel before the inertia of the cap or base B i or in any other convenient manner.

has been overcome, and the gas-check forced outward by the pressure of the gases generated by the explosion.

\It it obvious that I can, if desired, employ other means for securing together the two parts of the projectile with the gas-check between them, and for compressingthe said gas-check by hand, for the purpose above specified.

In the case of an explosive projectile or shell it is advantageous to arrange the fuse in a chamber or cavity D in the forward end of the bolt D, and to secure it therein by means of a screw-threaded ring or plug M, I thus provide for the removal and replacement of the fuse with the said bolt without disturbing other parts of the projectile and without detaching the parts of the fuse from each other. IVhen the explosion occurs and the pressure is developed in the chamber of the gun, this pressure, acting upon the movable cap or base B, drives the same forward relatively to the main portion or body A, and the packing or gas-check is subjected to pressure between y these parts, so that first the more easily compressible packing and then the harder or stiffer packing are squeezed outward into` the space or cavity around the projectile between the driving-rings E F. A gas-tight joint is thus made between the projectile and the barrel before the inertia of the main portion or body of the projectile is overcome and before the driving-ring E enters the riding.

It will be readily seen that the area of the annular surface of the cap or base B, which acts upon the packing or gas-check, is less than that of its rear surface, which is acted upon by the pressure generated by the explosion of the powdercharge in the gun. Therefore the pressure per square inch exerted upon the said packing or gas-check will Y at all times during the entire movement of the projectile through the bore of the gun be greater than that in rear of the projectilethat is to say, from the moment when the initial pressure is set up by the explosion until the projectile has left the muzzle of the gun the passage of the gas between the projectile and the bore of the gun is opposed by soft or ductile metal or other compressible or plastic material, which is undera higher pressure per square inch than that of the gas, the pressure from the chamber being opposed by a greater pressure. In other words, the pressure to which the packing between the two drivingrings is subjected not only insures the formation of a gas-tight joint before the said driving-rings have entered the riiiing, but during the entire passage of the projectile through the rifling of the gun the packing is pressed outward into the grooves of the riing, filling every little scratch and hole, and thus effectually preventing escape of the gases, and consequent erosion of the bore of the gun. The packing is, moreover, confined or imprisoned between the two driving-rings, and therefore cannot be displaced.

I prefer to so construct and arrange t-he parts that the packing forced or squeezed out from between the forward and rear portions of the projectile will fill the recess or cavity around the projectile between the two driv` ing-rings E F.

It will be seen that the driving-ring F has but little work to do in bringing about by its engagement with the ritling the rotation of the part B, to which it is attached. The said driving-ring F will therefore be but slightly damaged or abraded by the torsional or shearing stresses, the said part B being free to revolve on the body A of the projectile. Consequently the drivin g-ring F will act much more efficiently as a gas-check than the drivingring E, and will assist in effecting a complete obturation of the bore of the gun for t-he purpose above specified.

The ring or rings of packing forming the gas-check or obturator may be of various materials-for instance, lead, canvas and gum, asbestus, plumbago and tallow, jute or hemp mixed with composition such as that used for the manufacture of printers rollers.. In fact, any suitable material or composition or combination of materials may be used, which when subjected to pressure, as above described, will be forced outward, so as to tit gas-tight into the rfling of the gun.

I prefer to use some soft or plastic material to form the central ring or layer J of the packing, so that a comparatively small pressure will suffice to force it outward. The rings or layers H H may be made of sheet-lead or of lead pnlverized and mixed with wax to render it more difficult to force through a small opening; or they may be made of strong fibrous materiahwhich cannot be forced through a small opening by the pressure of the gases.

It is obvious that instead of employing parallel surfaces, between which the packing is arranged, I can, if desired, make the said surfaces conical, so that the distance between them increases from their inner to their outer IOO IIO

' edges, as shown,for example, in Fig. 2. Moreover, the packing may, if desired, lill' the space between the driving-rings E F before it is compressed, as also shown in this ligure.

I sometimes dispense with the rear driving- 'ri'ng, as'shown in Fig. 3.

It willbe seen thatin my improved projectile there is a driving-ring of' comparatively hard metal, such asv copper, and in rear of'this driving-ring is arranged between :the

Y two parts of the projectile vthe gas-check or 'obturator of softer or more dnctile metal, such as'lead, vor of yielding or plastic material, such v as those above mentioned. In the ,firing of' Il the projectile from the gun the said drivingring entersithe rifling andinsures the rotaj tion of the main portion or body of the projectile. Thevgas-ch'eck is expanded by the .'pressurefof the gases 'acting upon the rear' part of 'the projectile and enters the riling iin .rear ofthe said dri ving-rin g, thus preventing any escape of gas between the projectile and 'the barrel.

The location of the ygas check or obturator at` the base, rather than at any other convenient part of the projectile, is not imperative.

Having now particularly described and ascertained the nature of my said invention and in what/manner the same is'to be performed,

that such a ring has been used on aprojectile I wish it understood that I do not claim,gen ally or irrespectively of my improvements herein described, the employment of a ring of soft or ductile metalarranged between the l body of the projectile and a rear portion or base/movable relatively thereto, as I am aware toV serve both as a drivingring andas a gascheck; but in order to insure the requisite rotation of the projectile and at the same time effectually prevent anyv escape of gas between the projectile and. the barrel it is necessary f to employ rings of dierent kinds of material on the said projectile, as above described, one

ring of hard material to perform the work of rotating the projectile and another ring of material sufficiently ductile or plastic to be i forced into and to accurately iill the riiiing when subjected to the pressure of the gases,

in the manner above set fort-h.

What I claim is- I. A projectile having a drivin g-ring of copper or other metal suficiently hard to engagewith the riding and cause the rotation of the projectile about its axis, and a gascheck or obturator of metal or material softer or more ductile than that of the driving-ring,

for the purpose above specified.

2. A projectile having a driving-ring for insuring by itsy engagement with the ritling of a gun the rotation of the said projectile about its axis, and a separate gas-check or obturator of soft or ductile metal or other plastic or yielding packing adapted to be forced Voutward against the -'interior surface or bore 'of the gun by the pressure of the gases in rear of 'the' projectile.

3. The combination, with the body of apro- 'ject-ile havinga driving-ringthereon, of a longitudinally movable cap or base attached thereto, and a gas-check or obturator arranged between the said body and the movable capn or base, for the purposes above specified.

4. The combination, with thebody of a projectile having a driving-rin g thereon, of packin g arrangedat the Arear of thesaid body, and a `longitudinally-movable cap or base attached to the said body and having an annular sur- -face which vbears against the said packing,

whereby in the firing of the projectile from a gunthe said packing will be subjected to a pressure per square inch greater than thatin rear of the projectile, for the purpose above specified. i

5l The combinatiomwith the body of a proj ectile having a driving-ring thereon, of a longitudinally-movable cap or base, a gas-check or obturator arranged between the said body and the movable capvor'base, and a screwbolt whereby the said cap or base is secured to the body of the'proj ectile, and whereby the said gas-check or obturator may be compressed, substantially as and for the purposes set forth.

6. The combination, with the body of a proj ectile having a driving-ring thereon, of a cap or base attached to the said body so that it is capable of rotation relatively thereto, and a driving-ring secured upon the `said cap or base, substantially as and for the purposes set forth.

7. The combination, with the body of apro- `jectile or shell having adriving-ring thereon, vofy al longitudinally-movable vand rotatable cap or base attached thereto, a driving-ring secured upon the said cap or base, and a gascheck or obturator arranged between the said cap or base and the body of the projectile,

IOO

substantially as and for the purposes set forth.

S. The' combination, with the body of a pro- IIO jectile having a driving-ring thereon, of a j movable cap or base, a screw-bolt for secur` ing the said cap or base to the body ofv the projectile and having achamber for the fuse, and agas-check or obturator arranged between the said cap or base and the body of the projectile, substantially as and for' the purposes set forth.

9. The combination, with the body of a projectile having a driving-ring thereon, of a movable cap vor base also provided with acap or base and surrounding,` the said screwbolt, and a disk or annular piece secured to said cap or base in rear of the said packing, substantially as and for the purposes set forth.

l1. The combination, with the body of a projectile having a driving-ring thereon, of a movable cap or base attached thereto, and a gas-check or obturator arranged between the said body and the movable cap or base, and consisting of rings or annular pieces, one of which is formed of soft or easily-compressible or plastic material and others of harder or stiifer material, substantially as and for the purposes set forth.

l2. A projectile or shell having` a longitudinally-movable base or cap and provided with a driving-ring of copper or other metal sufficiently hard to insure the rotation of the projectile about its axis when fired from a gun, and with a gas-check or obturator of metal or other material which is softer or more ductile or plastic than that of the drivingring, arranged in rear of the said drivingring between the body of the projectile and the said movable base or cap, one or more chambers containing air or other easilycom pressible substance being provided between the vsaid body and the movable base or cap, for the purposes above specified.

13. A projectile or shell having a longitudinally-movable base or cap, and provided with a driving-ring of copper or other metal sufliciently hard to insure the rotation of the projectile about its axis when fired from a gun, and with a gas-check or obturator of metalor other material which is softer O r more ductile or plastic than that of the driving-ring, arranged in rear of the said driving-ring between the body of the projectile and the said movable base or cap, and a screw-bolt whereby the said base or cap is secured to the body of the projectile, and which can be screwed up by hand to compress the said gas-check, one or more chambers containing air or other easily-compressible substance bein g provided between the said body and the movable base or cap, for the purposes above specified.

In testimony whereof lhave hereunto signed my name in the presence of two subscribing witnesses.

HIRAH STEVENS MAXLM.

Witnesses:

DAvID YOUNG, CHAs. B. BURDON. 

